IDT821611J IDT, Integrated Device Technology Inc, IDT821611J Datasheet - Page 10

• Manufacturer Part Number: IDT821611J
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT821611J

• Number Of Channels: 1
• On-hook Transmission: Yes
• Polarity Reversal: Yes
• On-chip Ring Relay Driver: Yes
• Operating Supply Voltage (typ): 3.3/5V
• Operating Temp Range: -40C to 85C
• Package Type: PLCC
• Operating Temperature Classification: Industrial
• Pin Count: 32
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

hook, the bridging resistors should be chosen as that:
event occurs, otherwise, the loop is in on-hook state.
RELAY DRIVERS CONTROL
control the external ring relay. This ring relay driver is active only in
Ringing state. It is an internal transistor with the emitter internally
connected to BGND and the collector as the driver output (see
During ringing, the ring relay driver is activated and the ringing source is
connected by an external ring relay to the Tip and Ring lines through
ring feed resistors.
and RYOUT2) on the chip. They are open-collector drivers with emitters
internally connected to BGND. The two drivers allow for direct operation
of external test relays. The digital pins D1 and D2 are used to control the
relay drivers RYOUT1 and RYOUT2 respectively. Logic low on D1 and
D2 activates their respective relay drivers.
IDT821611
Functional Description
Ringing
Source
If R
Where: R
If the line resistance is less than R
The IDT821611 provides an on-chip ring relay driver (RINGOUT) to
The IDT821611 also provides two additional relay drivers (RYOUT1
Tip Line
Ring Line
LMAX
R
----------
R
B1
BGND
3
+
-
=
FEED
is the maximum line resistance to be detected as an off-
R
2
R
----------
R
B2
4
Figure 3 Relay Drivers Schematic
= R
K
R
R
=
1
Figure 2 Ring-trip Detection
Ring Relay
1
(
------------------------------------------------- -
R
K
+ R
K
R
LMAX
R
RINGOUT
2
R
LMAX
R
R
R
R
R
R
+
B1
B2
3
4
F
F
R
FEED
)
LMAX
BGND
, it means that an off-hook
C
C
RT2
RT1
RINGOUT
DA
DB
A(TIP)
B(RING)
SLIC
RYOUT1
RYOUT2
Figure
3).
8
DC FEEDING
Figure
and a capacitor C
See
combination of R
ms. The value of C
The IDT821611 provides constant-current feeding as shown in
Notes:
1.
2.
3.
The feed current is programmable. Two resistors R
The feed current I
The polarity reversal time is controlled by C
(volts)
Figure 5.
VAB
R
L
4.
V
V
I
V
a
b
60
FEED
AB
AB
AB
0
=
=
=
=
0.857 V
I
0.857 V
Figure 5 DC Feed Programming Circuit
I
L
L
Figure 4 DC Feeding Characteristics
R
------------------------------------
R
Note 3
DC1
DC
L
DC1
DC
′
=
(
(
Feed current is programmed by R
1250
form the network for programming the feed current.
FEED
+
and R
can then be calculated by the following equation:
------------------------------------R
R
BAT
BAT
A(TIP)
B(RING)
DC1
R
DC2
1250
is calculated by the following equation:
+
+
+
DC2.
SLIC
1.2
3.3
R
DC2
) I
) I
A typical polarity transition time is 1.5
–
–
RDC
RSN
I
L
L
L
L
(mA)
R
------------------------------------
′
R
------------------------------------
,
where
DC1
DC1
Note 2
300
300
+
+
R
R
R
DC2
DC2
L
DC1
′
LONG HAUL SLIC
=
and R
R
R
DC
October 8, 2003
R
DC1
DC2
L
DC2.
+
and its parallel
2R
DC1
Note 1
F
and R
C
30
DC
DC2
,